All categories

3 years ago

Calculate the concentrations of all species present in a 0.26 M solution of ethylammonium chloride (C2H5NH3Cl).

Chemistry

1 answer:

Alina [70]3 years ago

5 0

Answer:

0.00000223

Explanation:

pKa for C2H5NH3+ = 10.7

pKw = 14.0

pKa + pKb = pKw

10.7 + pKb = 14.0

pKb = 14.0 - 10.7

pKb = 3.30

C2H5NH3Cl is a salt of ethylamine and HCl so it will dissolve in water to produce C2H5NH3^+ + Cl^-

The base hydrolysis reaction: C2H5NH3^+(aq) + H2O(l) <=> C2H5NH2(aq) + H3O^+(aq)

This reaction is described by Kb.

Kb = [C2H5NH2][H3O^+]/[C2H5NH3^+]

Let [C2H5NH2] = [H3O^+] = x,

so [C2H5NH3^+] = 0.26 - x

Kb = x^2/(0.26 - x) = 2.00 x 10^-11

Let's solve for x. In this equation, It is possible to solve without the use quadratic equation. So we can assume that 0.26 - x is approximately equal to 0.26. We won't know until we do the calculation.

We get: x^2 + 2.00 x 10^-11x - 4.99 x 10^-12 = 0

With the use of a quadratic calculator.

x = 2.23 x 10^-6 M = [C2H5NH2] = [H3O^+]

0.26 - x is just 0.26 M in this problem because 2.23 x 10^-6 M is insignificant.

[C2H5NH3^+] = 0.26 M = [Cl^-]

NOTE:

pH = -log [H3O^+] = -log(2.23 x 10^-6) = 5.65

Ka is the acid dissociation constant

Kb is the base dissociation constant

You might be interested in

What is the boiling point of 5 ml of alcohol

NeTakaya

173.1f is the answer I believe, please let me know if I'm wrong then I would try to make up for it

4 0

3 years ago

guys please help me WILL MARK BARINLIEST If you have 5.7 x 10^24 molecules of O2 at STP, how many liters of O2 do you have? must

zmey [24]

Answer:

212.8 dm^3 or L

Explanation:

1 mole of any sub=6.02×10^23 molecules

X mole of O2=5.7×10^24 molecules

X mole=5.7×10^24/6.02×10^23

=9.5 mole

1 mole of any gas at stp=22.4 dm^3

Therefore, 9.5 mole of O2 will be 22.4×9.5

=212.8 dm^3

5 0

2 years ago

The atomic masses of 151eu and 153eu are 150.919860 and 152.921243 amu, respectively. The average atomic mass of europium is 151

vitfil [10]

Answer:- The natural abundance of $^1^5^1_E_u$ is 0.478 or 47.8% and $^1^5^3_E_u$ is 0.522 or 52.2% .

Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:

Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)

We have been given with atomic masses for $^1^5^1_E_u$ and $^1^5^3_E_u$ as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.

Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of $^1^5^1_E_u$ as n then the abundance of $^1^5^3_E_u$ would be 1-n .

Let's plug in the values in the formula:

$151.964=150.919860(n)+152.921243(1-n)$

151.964=150.919860n+152.921243-152.921243n

on keeping similar terms on same side:

$151.964-152.921243=150.919860n-152.921243n$

$-0.957243=-2.001383n$

negative sign is on both sides so it is canceled:

$0.957243=2.001383n$

$n=\frac{0.957243}{2.001383}$

$n=0.478$

The abundance of $^1^5^1_E_u$ is 0.478 which is 47.8%.

The abundance of $^1^5^3_E_u$ is = $1-0.478$

= 0.522 which is 52.2%

Hence, the natural abundance of $^1^5^1_E_u$ is 0.478 or 47.8% and $^1^5^3_E_u$ is 0.522 or 52.2% .

3 0

3 years ago

For every 4 hours that Alexa babysit her younger sister, her mom pays her $50

tiny-mole [99]

Answer:12.5

Explanation: Divide 50$ by the 4 hours and you will get 12.5 which is $12.50.

7 0

3 years ago

Read 2 more answers

Explain the two main physical/ chemical processes by which carbon dioxide molecules in the air move to the cells of phytoplankto

VARVARA [1.3K]

Answer:

The two physical/ chemical processes by which carbon dioxide molecules in the air move to the cells of phytoplankton in the ocean are the photosynthesis and the biological carbon pump.

Explanation:

The biological carbon pump is the action of organisms to move carbon during chemical and biological interactions from the surface into the deeper ocean and then to rocks.

The biological carbon pump its composed of three processes, which are the photosynthesis, the gravity and the food web interactions. They are all part of the carbon cycle.

During the photosynthesis, the phytoplankton take up carbon dioxide from the atmosphere that is dissolved in the surface water, and receives the energy from the sun to turn it into glucose and oxygen.

In the cells of the phytoplankton, glucose is transformed into other organic compounds. This material has organic carbon that can end in two ways: it is incorporated to marine organisms during the food web interactions or it can be remineralised forming calcium carbonate in the ocean surface.

The remineralization can be done by many organisms to build its shells or skeletons, or by chemical processes that happen in the ocean. This process allows more carbon dioxide to enter the water and to continue the cycle.

So when marine organisms die, all its organic components sink into the bottom of the ocean and carbon-rich sediments are form. And after millions of years, these sediments turn into rocks after going through chemical and physical phenomenon.

3 0

3 years ago